The electrophoretic softness of the surface of Staphylococcus epidermidis cells grown in a liquid medium and on a solid agar

Kiers, Paskal J. M.; Bos, R.; Mei, Henny C. van der; Busscher, Henk J.

doi:10.1099/00221287-147-3-757

Cited by 58 publications

(50 citation statements)

References 21 publications

(20 reference statements)

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“…The above electrophoresis theory of soft particles has been applied to analyze the electrophoretic mobility data of biological colloids such as cells and their model particles [24][25][26][27][28][29][30][31][32][33][34][35]. Ohshima [36,37] proposed a theory of electrophoresis of soft particles in concentrated suspensions.…”

Section: Electrophoretic Mobility Of Soft Particlesmentioning

confidence: 99%

Theory of electrostatics and electrokinetics of soft particles

Ohshima

2009

Science and Technology of Advanced Materials

138

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We investigate theoretically the electrostatics and electrokinetics of a soft particle, i.e. a hard particle covered with an ion-penetrable surface layer of polyelectrolytes. The electric properties of soft particles in an electrolyte solution, which differ from those of hard particles, are essentially determined by the Donnan potential in the surface layer. In particular, the Donnan potential plays an essential role in the electrostatics and electrokinetics of soft particles. Furthermore, the concept of zeta potential, which is important in the electrokinetics of hard particles, loses its physical meaning in the electrokinetics of soft particles. In this review, we discuss the potential distribution around a soft particle, the electrostatic interaction between two soft particles, and the motion of a soft particle in an electric field.

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Section: Electrophoretic Mobility Of Soft Particlesmentioning

confidence: 99%

Theory of electrostatics and electrokinetics of soft particles

Ohshima

2009

Science and Technology of Advanced Materials

138

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“…One example is the prediction of cell surface potentials based on a hard sphere model 27,28 often deviates from the real surface potential of the microorganisms. [29][30][31] Another is the observed magnitude of attractive or repulsive forces between microbes and surfaces at short and long separation distances. [32][33][34][35][36][37][38][39] In addition, the type and extent of the interaction may depend on the amount, composition, and configuration of the bound surface macromolecules.…”

Section: Introductionmentioning

confidence: 99%

“…The theory has been widely used to predict the surface potential of microbes and to evaluate the degree of electrophoretic softness of polymeric layers. 31,[44][45][46] In addition, several studies have recently attempted to characterize the chemistry of cell membrane or polymeric layers by combining macroscopic (e.g., zeta potential, surface hydrophobicity, potentiometric titration) and molecular (e.g., scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy) techniques. [47][48][49] However, it is still not straightforward to quantify and generalize macromolecule-related variations in cell surface properties due to the complexity of the cell surface and the sensitivity of macromolecules to the cell type (e.g., species, serotypes, or strains) 19,35,50 and environmental conditions (e.g., growth stage, temperature, and solution chemistry).…”

Section: Introductionmentioning

confidence: 99%

“…As mentioned briefly in the introduction, soft particle theory has been developed to interpret the EPM behavior of polyelectrolyte-coated particles [40][41][42][43] and has been applied to bacteria to predict their surface potential. 31,[44][45][46] The theory allows one to determine two parameters: electrophoretic softness (λ ) and volumetric fixed charge density (F fix ). The parameter λ characterizes the resistance applied to the liquid flow in the cell surface region, and the value of λ -1 represents the characteristic distance from the slipping plane to the outermost part of the polymeric layer.…”

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Surface Characteristics and Adhesion Behavior of Escherichia coli O157:H7: Role of Extracellular Macromolecules

et al. 2009

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Experiments were conducted using enterohemorrhagic Escherichia coli O157:H7 cells to investigate the influence of extracellular macromolecules on cell surface properties and adhesion behavior to quartz sand. Partial removal of the extracellular macromolecules on cells by a proteolytic enzyme (proteinase K) was confirmed using Fourier transform infrared spectroscopy analyses. The proteinase K treated cells exhibited more negative electrophoretic mobility (EPM) at an ionic strength (IS) e 1 mM, a slightly lower isoelectric point, and were less hydrophobic as compared to the untreated cells. Potentiometric titration results indicated that the total site concentration (i.e., the total amount of exposed functional groups per cell) on the treated cells was approximately 22% smaller than the untreated cells, while the dissociation constants were almost identical. Analysis of the EPM data using soft particle theory showed that the removal of extracellular macromolecules resulted in polymeric layers outside the cell surface that were less electrophoretically soft. The more negative mobility for the treated cells was likely due to the combined effects of a change in the distribution of functional groups and an increase in the charges per unit volume after enzyme treatment and not just removal of extracellular macromolecules. The proteolytic digestion of extracellular macromolecules led to a significant difference in the cell adhesion to quartz sand. The adhesion behavior for treated cells was consistent with DLVO theory and increased with IS due to less negativity in the EPM. In contrast, the adhesion behavior of untreated cells was much more complex and exhibited a maximum at IS ) 1 mM. The treated cells exhibited less adhesion than the untreated cells when the IS e 1 mM due to their more negative EPM. However, when the IS g 10 mM, a sudden decrease in the removal efficiency was observed only for the untreated cells even through EPM values were similar for both treated and untreated cells. This result suggested that an additional non-DLVO type interaction, electrosteric repulsion, occurred at higher IS (g10 mM in this study) for the untreated cells due to the presence of extracellular macromolecules that hindered cell adhesion to the quartz surface. This finding provides important insight into the role of macromolecule-induced E. coli O157:H7 interactions in aquatic environments.

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“…Hence, the soft layer at the cell surface plays an important role in bacterial attachment, and that softness has been analyzed (2,9,12,19). Recently the cell surface softness of fibrillated and nonfibrillated streptococcal cell surfaces has been directly measured with an atomic force microscope (AFM) (21,22).…”

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confidence: 99%

Electrophoretic Mobility of Bacillus subtilis Knockout Mutants with and without Flagella

et al. 2003

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Mutants of Bacillus subtilis 168 strain were obtained by inactivation of a specific gene by homologous recombination with the plasmid pMutinT3. The cell surface properties of these strains were characterized by measuring the electrophoretic mobility of the cells as a function of pH and ionic strength. The surface properties were different for the strains possessing flagella on their cells and strain FlgB, having no flagellum, due to knockout of the corresponding gene. The cell surface properties of the strains possessing flagella become similar to those of strain FlgB after acid treatment. It was confirmed that the acid treatment degraded the flagella without causing any apparent structural change on the cell surface via observations made using atomic force microscopy, transmission electron microscopy, and scanning electron microscopy. These results indicate that the flagella are a key factor influencing cell surface properties.Many microbes exist attached to various surfaces in natural environments. The attachment of microbial cells is greatly influenced by cell surface properties, and the electric charge on a microbial cell surface has been a key feature for characterizing cell surface properties. To estimate the electric charge, the velocity of movement of the cells suspended in a buffer under an electric field has been measured. The electrophoretic mobility (EPM) of the cells, obtained by dividing the velocity by the strength of the electrical field, has been used to estimate the electric charge on the cell surface.Recently, strange electrokinetic behavior of some colloidal particles, including bacterial cells, has been noticed, in which the colloidal particles can be mobilized in an electric field even when the ionic strength of the buffer becomes quite high (2,8,12,18,19). Conventional thought is that colloidal particles cease to move under condition of high ionic strength due to depression of the thickness of the electric double layer by counter ions. This discrepancy between experimental results and the conventional theory demands reconsideration of the EPM value and the cell surface properties estimated from EPM data.Ohshima (15, 16) has proposed a new theory that can explain the strange behavior of some colloidal particles. According to this theory, the electrical charge in a polymer layer existing at the particle surface is the driving force that mobilizes the colloidal particles under conditions of high ionic strength. The depression of the electrical double layer at the site bearing the electrical charge in the polymer layer is considered not to be large enough to affect the particle EPM by permeating counter ions through the polymer layer under conditions of high ionic strength. Ohshima's theory enables us to characterize the properties of colloids having a polymer layer at the surface. Bacterial cells are typical examples of colloids that have a polymer layer at the surface due to the presence of a soft polyelectrolyte layer on their surfaces.We first reported that the presence of the soft polymer...

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The electrophoretic softness of the surface of Staphylococcus epidermidis cells grown in a liquid medium and on a solid agar

Abstract: A soft, highly negatively charged polyelectrolyte layer was inferred by microelectrophoresis for all the staphylococcal cell surfaces, regardless of whether staining had indicated the presence of a capsule or slime layer.

Cited by 58 publications

References 21 publications

Theory of electrostatics and electrokinetics of soft particles

Theory of electrostatics and electrokinetics of soft particles

Surface Characteristics and Adhesion Behavior of Escherichia coli O157:H7: Role of Extracellular Macromolecules

Electrophoretic Mobility of Bacillus subtilis Knockout Mutants with and without Flagella

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